1. Field of the Invention
The present invention relates to a technology for rewriting a firmware in a device which executes the firmware to realize inherent functions thereof, and more particularly relates to a technology for rewriting a firmware in a home-use electronic device, such as a DVD recorder or the like, capable of obtaining the firmware using a removable storage medium, network, broadcast wave or the like.
2. Description of the Related Art
Devices such as DVD recorders or the like generally realize inherent functions thereof, using a firmware stored in a nonvolatile memory. The firmware may be updated into a new version when, for example, a bug is corrected or a new function is added. For example, Japanese Laid-Open Patent Publication No. 08-255083 discloses a technology for updating an existing firmware in a device into a new version.
In general, devices such as DVD recorders or the like perform version-up of (i.e., update the version of) a firmware included therein, using a media update function. The media update function is to read a new firmware from a removable storage medium such as a DVD or the like, write the firmware onto a nonvolatile memory, and thus update the firmware.
Some of the recently developed devices also have a network update function. The network update function is to obtain a new firmware using a broadcast wave or a data communication network, write the new firmware onto a nonvolatile memory, and thus update the firmware. The processing for obtaining and updating the firmware is executed with no involvement of the user.
The update processing of the firmware is generally automated and very rarely fails, but there is still a possibility of failure. When the firmware update fails, the firmware cannot be executed and so the functions of the device stop being provided.
There are other cases where the firmware cannot be normally executed even if the firmware update does not fail. Such cases are, for example, when the firmware has one or more bugs, the firmware is destroyed due to a program glitch, the parameters of the firmware are rewritten by an untrustworthy program. Furthermore, there is a case where the parameters of the firmware are set in an incorrect manner due to an unexpected operation of the user. This is because the user needs to set parameters to his or her home appliance (e.g. a DVD recorder) which has become complicated in software function and operation just like a PC. Also, the user needs to operate the appliance in combination with his or her PC. In each case noted above, the functions of the device stop being provided.
In many cases where the firmware is not normally executed, the only step the device can take is to use the media update function to rewrite the existing firmware with executable firmware. Even if the device has a network update function, such a function cannot be used in most of the cases for the following reason. Although the device is designed such that at least drives and the like thereof operate in such cases, the section for receiving a broadcast wave or the like does not necessarily operate. Namely, the network update function is not suitable for recovering firmware.
In a situation where the media update function needs to be used for recovery of the firmware, for example, the device cannot possibly be used for an extended period of time. The reason is that the user has to wait until a storage medium having executable firmware stored therein becomes available.
For example, when the user requests a service center or the like for a DVD having the firmware storing therein, the DVD is sent by the conventional mail and it takes several days to several weeks for the DVD to be delivered to the user. In addition, a monetary burden is imposed on the user. Especially when the service center does not have any stock of the DVD, the service center has to order the DVD from the manufacturer, which further extends the time required until the user obtains the DVD. Generally, service centers have DVDs sent from the manufacturer or the like in stock but do not create the DVDs themselves. Such a situation also keeps the user waiting unable to use the device for an extended period of time.
It is preferable that the user can get the firmware back to normal as soon as possible, in the case where the user set an inappropriate parameter. In the near future, the user must set many types of parameters, each of which takes a wider range of values, to a home appliance such as a DVD recorder like a PC. Also, each range of parameter values becomes large. It is neccessary to consider that the user may set unexpected parameters due to a lot of flexible settings.